1. Field of the Invention
The disclosure relates to a system and a method for semiconductor structure measurement, and particularly, to a system and a method for via structure measurement.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
As consumer demand for lighter and smaller electronic devices continues to grow, semiconductor manufacturing techniques are advancing to meet such requirements. In particular, a new technique, known as the 3D stacking technique, has been developed. The 3D stacking technique utilizes through silicon via (TSV) technique, which involves vertically stacking a plurality of chips, to reduce the overall package size. TSV technique uses a via structure to vertically connect a plurality of chips, and therefore can replace wire bonding technique to save the costs of routing and intermediate layers required by wire bonding technique.
Due to the aforementioned advantages, TSV technique is popular among small-sized electronic devices with high aspect ratio. Accordingly, measurement for the via structures formed according to TSV technique has become an issue of importance. Generally, large sized via structures, e.g. via structure with aperture greater than 10 micrometers, can be measured by optical microscope. However, for via structures with high density, e.g. via structures with via/space ratio greater than 1, via structures with high aspect ratio, e.g. via structures with aspect ratio greater than 10, or via structures with small aperture, e.g. via structures with aperture smaller than 10 micrometers, most of the current measuring methods, such as measuring methods utilizing electronic microscopes or spring probes, are slow and destructive. In other words, currently, the parameters, especially the depth and the bottom profile, of via structures with high density, high aspect ratio or small aperture cannot be measured in an optical and non-destructive way.
On the other hand, TSV technique is progressing toward high-density and high aspect-ratio applications. According to the International Technology Roadmap for Semiconductor (ITRS) published in 2008, the aperture of all TSVs in the market are estimated to be smaller than 1.4 micrometer, and the aspect ratio thereof are estimated to be greater than 10.
Accordingly, there is a need to design a system and a method for via structure measurement in which the depth and bottom profile of a via structure can be measured in a non-destructive way. This disclosure provides such system and method.